Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, orthogonal frequency-division multiple access (OFDMA) systems, and 3GPP Long Term Evolution (LTE).
Generally, a wireless multiple-access communication system can simultaneously support communication for multiple wireless terminals. Each terminal communicates with one or more base stations via transmissions on the forward and reverse links. The forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations.
Wireless networks enable the wireless terminals to establish wireless connections with the base stations over remote private or public networks using radio, satellite, and mobile phone technologies. An example of a wireless network includes a wireless wide area network (WWAN). A WWAN uses mobile telecommunication cellular network technologies provided by the multiple-access systems described above to send and receive data. Wireless terminals with WWAN connectivity can support multiple WWAN data technologies, but the wireless terminals often are able to support only one WWAN technology at any given time.